Glycine latifolia Random survey

Sclerotinia sclerotiorum causes Sclerotinia stem rot, which results in significant yield losses in soybean (Glycine max) in epidemic years. Varying levels of partial resistance to Sclerotinia stem rot have been identified in cultivated soybean. However, this resistance is conditioned by multiple quantitative loci each with small effects, some of which alter plant development and/or architecture. Cultivated soybean has a relatively narrow genetic base and no fully resistant soybean varieties have been found to date. In contrast, wild soybean species show much wider ranges of responses to infection by S. sclerotiorum. While most accessions, like most cultivated soybean lines, are killed by the fungus, a small number of accessions show high levels of resistance and survive multiple inoculations with the fungus. The objectives of this study are to: 1) generate mapping populations in two perennial Glycine species that segregate high levels of resistance to Sclerotinia stem rot and characterize the responses of derived recombinant inbred lines (RILs) to S. sclerotiorum infection; 2) Identify single nucleotide polymorphisms (SNPs) and construct high-density genetic maps for the RIL population(s) produced in Objective 1; and 3) identify loci that contribute to Sclerotinia stem rot resistance in two perennial Glycine accessions and evaluate their novelty relative to loci previously identified in G. max. The project will address the goals and priorities of the Sclerotinia Initiative by genetically characterizing resistant plant germplasm resources and developing genomic resources to identify chromosomal regions conditioning high levels of resistance to Sclerotinia stem rot in perennial Glycine species.核盘菌（Sclerotinia sclerotiorum）可引发菌核茎腐病（Sclerotinia stem rot），在流行年份会造成大豆（Glycine max）出现显著产量损失。栽培大豆中已鉴定出对菌核茎腐病的不同水平的部分抗性，但该抗性受多个效应微弱的数量性状位点（quantitative loci）调控，其中部分位点会改变植株发育进程与/或株型结构。栽培大豆的遗传基础相对狭窄，截至目前尚未发现完全抗病的大豆品种。与之相对，野生大豆属物种对核盘菌侵染的响应范围更广：尽管多数种质材料与多数栽培大豆品系一样会被该真菌致死，但少量种质材料表现出高水平抗性，可经受多次真菌接种后存活。 本研究的目标如下：1）在两个多年生大豆属物种中构建分离出高水平菌核茎腐病抗性的作图群体，并对衍生的重组自交系（recombinant inbred lines, RILs）对核盘菌侵染的响应特征进行表征；2）为目标1中获得的重组自交系群体鉴定单核苷酸多态性（single nucleotide polymorphisms, SNPs）并构建高密度遗传图谱；3）在两个多年生大豆属种质材料中鉴定调控菌核茎腐病抗性的位点，并评估其相较于此前在栽培大豆（G. max）中鉴定到的位点的新颖性。 本项目将通过遗传表征抗病植物种质资源，开发可用于定位多年生大豆属物种中调控菌核茎腐病高水平抗性的染色体区域的基因组资源，从而达成核盘菌倡议（Sclerotinia Initiative）的目标与优先事项。